Method and apparatus for delivering an api-containing liquid to an edible substrate

A method of delivering an active pharmaceutical ingredient (API) to a substrate, the method comprising the steps of:

• bringing the substrate into alignment with a dosing station having a conduit that terminates at a dosing head, and a pump in fluid communication with the conduit;
• causing the pump to drive an API-containing liquid out of the dosing head;
• measuring a pressure and a temperature of the API-containing liquid in the conduit during the causing step;
• and
• determining a characteristic based at least in part on the step of measuring the temperature or the pressure, wherein the characteristic comprises at least one of a faulty condition of the pump, a degradation of the API, a clog or leak in the conduit, a change of density of the API-containing liquid, a change of viscosity of the API-containing liquid, and a change of concentration of the API in the API-containing liquid.